Further: The last one on this list (J91) has the symmetry of
a 2-gonal prism: three orthogonal 2-fold axes and three planes of symmetry
each containing two axes. The one before it (J90) has the symmetry of a
2-gonal antiprism: three 2-fold axes and three planes of symmetry of which
two pass halfway between axes. Find another with 2-gonal anti-prism symmetry.